DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.20658#0327
COLOURING SUBSTANCES.
313
water. This water is changed every two days, until the surface appear quite free from extraneous
substances, and the colour ceases to blacken round the edges of ihe vessel: but this preparation
is tedious and expensive, owing to the great quantity of distilled water required. When this red
is perfectly prepared and purified with spirits of wine, it may be used in all sorts of painting.
Lake. Colours known by this,name are formed by the combination of the alumine of earth,
which is the basis of alum, or of the calx or oxydeof tin with the colouring matters of vegetables:
they are chiefly red, and of various qualities according to the substances from which they are
drawn. The best of what is usually sold in the shops is made from scarlet rags, in the following
manner: Take a pound of the best pearl ashes and, dissolving them in two quarts of water,
filter the mixture through paper. To this solution add other two quarts of water, and putting in
a pound of scarlet rags in shreds perfectly clean, boil them in a pewter kettle until they have
completely parted with their colour: then take out the rags and press them, dipping them in
water and again pressing them, that all the fluid they had taken up may be recovered and put
back to the rest. Again take another pound of the same rags or shreds and treat them in the
same manner as the first pound ; and in the same way a third and a fourth pound. While this
is doing a pound of the bone of the cuttle-fish is dissolved in a pound of strong aqua fortis in a
glass receiver, adding more of the bone if it produce any ebullition in the aqua fortis; and
straining off this solution through flannel add it to the other, observing whether on putting in
the last part of it any effervescence is occasioned. If this happen in any considerable degree ;
more bone must be dissolved as before, and gradually added to the liquor, till no ebullition is
observed. When this is properly conducted the liquor will soon become clear and colourless,
and the tinging particles extracted from the shreds, together with the cuttle-fish bonewill subside
to the bottom, forming a crimson sediment which is the lake. The water is then poured off, and
two gallons of hard spring water put to the lake, well mixed and poured off. This operation with
the water must be repeated four or five times ; but if the proper hard water cannot be procured,
or if the lake appear too much of a purple hue, half an ounce of alum should be added to each
quantity of water before it be used. When the lake is thus sufficiently freed from the salts, the
water is drained from it by a filter covered with a linen cloth, which has been so much worn as
to have no nap remaining on its surface. When the lake has been thus well drained it is dropped
on clean boards, by means of a proper funnel, through which the substance passes in drops
forming small cones or pyramids. In this state the lake remains till it is quite dry, and the pre-
paration is completed.
There is also a lake extracted from madder, which is not indeed of so bright and rich a colour
as the others, but it has this great advantage that it stands much better, and may be made to
answer many of the purposes to which Florence lake is applied.
Rose Lake commonly called Rose Pink, is prepared from chalk coloured with the extract of
Brazil or Campeachy wood; but as it does not stand in oil or water it is seldom used, excepting
by house-painters or paper-stainers, who secure it by varnish, when it answers very well.
Indian Red is a very useful colour, supplying in many cases the place of lake, and stands
well both in water and oil; but the genuine sort is difficult to be procured, as it comes from
India, and is often counterfeited in this country. The common Indian red has a tint bordering
on scarlet whereas the genuine colour inclines to a purple. It may be made in the following
way.
4 l Take
313
water. This water is changed every two days, until the surface appear quite free from extraneous
substances, and the colour ceases to blacken round the edges of ihe vessel: but this preparation
is tedious and expensive, owing to the great quantity of distilled water required. When this red
is perfectly prepared and purified with spirits of wine, it may be used in all sorts of painting.
Lake. Colours known by this,name are formed by the combination of the alumine of earth,
which is the basis of alum, or of the calx or oxydeof tin with the colouring matters of vegetables:
they are chiefly red, and of various qualities according to the substances from which they are
drawn. The best of what is usually sold in the shops is made from scarlet rags, in the following
manner: Take a pound of the best pearl ashes and, dissolving them in two quarts of water,
filter the mixture through paper. To this solution add other two quarts of water, and putting in
a pound of scarlet rags in shreds perfectly clean, boil them in a pewter kettle until they have
completely parted with their colour: then take out the rags and press them, dipping them in
water and again pressing them, that all the fluid they had taken up may be recovered and put
back to the rest. Again take another pound of the same rags or shreds and treat them in the
same manner as the first pound ; and in the same way a third and a fourth pound. While this
is doing a pound of the bone of the cuttle-fish is dissolved in a pound of strong aqua fortis in a
glass receiver, adding more of the bone if it produce any ebullition in the aqua fortis; and
straining off this solution through flannel add it to the other, observing whether on putting in
the last part of it any effervescence is occasioned. If this happen in any considerable degree ;
more bone must be dissolved as before, and gradually added to the liquor, till no ebullition is
observed. When this is properly conducted the liquor will soon become clear and colourless,
and the tinging particles extracted from the shreds, together with the cuttle-fish bonewill subside
to the bottom, forming a crimson sediment which is the lake. The water is then poured off, and
two gallons of hard spring water put to the lake, well mixed and poured off. This operation with
the water must be repeated four or five times ; but if the proper hard water cannot be procured,
or if the lake appear too much of a purple hue, half an ounce of alum should be added to each
quantity of water before it be used. When the lake is thus sufficiently freed from the salts, the
water is drained from it by a filter covered with a linen cloth, which has been so much worn as
to have no nap remaining on its surface. When the lake has been thus well drained it is dropped
on clean boards, by means of a proper funnel, through which the substance passes in drops
forming small cones or pyramids. In this state the lake remains till it is quite dry, and the pre-
paration is completed.
There is also a lake extracted from madder, which is not indeed of so bright and rich a colour
as the others, but it has this great advantage that it stands much better, and may be made to
answer many of the purposes to which Florence lake is applied.
Rose Lake commonly called Rose Pink, is prepared from chalk coloured with the extract of
Brazil or Campeachy wood; but as it does not stand in oil or water it is seldom used, excepting
by house-painters or paper-stainers, who secure it by varnish, when it answers very well.
Indian Red is a very useful colour, supplying in many cases the place of lake, and stands
well both in water and oil; but the genuine sort is difficult to be procured, as it comes from
India, and is often counterfeited in this country. The common Indian red has a tint bordering
on scarlet whereas the genuine colour inclines to a purple. It may be made in the following
way.
4 l Take